Most existing "for-fee" public communication networks, such as Motorola's DataTAC.TM. data radio systems or even cellular phone systems, include a "Home Location Register" commonly referred to as an HLR, which is a database of the network's subscribers. The network operator must create a record in this database for each subscriber. Subscribers are usually identified by a unique ID number. When a subscriber desires services from the network, he (actually his device) must register onto the network, supplying the ID number and possibly some additional authentication information, such as a password or historical information relating to the subscriber. This information is checked (i.e. authenticated) by the network against the subscriber's record in the HLR. All subsequent services are then billed to the identified subscriber. This mechanism works well for subscribers that use enough services for it to be worthwhile to bill them. For some applications however, such as residential alarm systems and others, this is not the case. The number of "subscribers" is very large and it is expensive to add them to the HLR database and also increases the database size slowing access for all subscribers.
Another authentication arrangement based on a register of identified subscribers can be found in U.S. Pat. No. 4, 896,319 "Identification and Authentication of End User Systems for Packet Communications Network Services". Other public/private key approaches for authenticating IP packets, such as is described in U.S. Pat. No. 5,511,122 "Intermediate Network Authentication" require a database of the sender's public keys. This suffers from the same disadvantages as the HLR method described above.
Existing "free" communication systems (such as the Internet) often have no authentication mechanisms at all, because it is not necessary to bill anyone. Gaining access to the Internet via an "Internet Service Provider", or ISP, is very similar to the "for-fee" HLR mechanism described above. Each ISP has a database of their subscribers who usually use a password to authenticate their access to the ISPs services.
There is a need for an improved method of authentication in a data or radio data network, preferably one in which the infrastructure does not require an extensive list of all users seeking authentication.